Well barrier apparatus and associated methods

ABSTRACT

A barrier forming apparatus is deployable through a conduit component in a well. The apparatus has a snap latch that removably couples to a work string. A mandrel element in the apparatus is selectively moveable with the coupling element. A plurality of locator dogs on the apparatus are spring biased and are activated when pressure is applied to a piston in the apparatus, which release the locator dogs. Once activated, the locator dogs engage a first grove the in the conduit component. When the work string is pulled up while the apparatus is held by the locator dogs, a plurality of locking dogs are activated by movement of a mandrel element caused by the work string. The locking dogs engage second grooves in the conduit component. Continued pulling of the work string moves a cone attached to a distal end of the mandrel element, and the moving cone deforms a barrier element positioned between an end of the apparatus&#39; housing and the cone. The deformed barrier element forms a barrier in the conduit component between upper and lower completions. Removal of the barrier is achieved by reversing the steps. The apparatus can be used to isolate an expandable sand screen section below the conduit component.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a non-provisional of U.S. Provisional Application Ser. No. 60/866,902, filed 22 Nov. 2006, which is incorporated herein by reference and to which priority is claimed.

BACKGROUND

Some wells may have an Expandable Sand Screen (ESS) system, other type of screen, slotted liner, or other type of completion open to the formation. In these wells, it is often necessary to use a valve or other device between the upper and lower completions to reduce or stop fluid loss to the formation. In many applications, the valves are kept closed when needed and are then opened after the upper completion is run, but the valves can never be closed again. Although some valves (such as ball valves) can be opened and closed multiple times, these types of valves typically have a restricted inner diameter that prevents there use with an ESS system. For example, the restricted inner diameter of such valves cannot accommodate the various tools associated with the ESS system, such as an expansion tool.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1L schematically illustrate a barrier plug according to the present disclosure used with a lower completion having expandable sand screen system.

FIG. 2 illustrates one embodiment of a barrier plug according to the present disclosure.

FIGS. 3A-3C illustrate detailed sectional views of the barrier plug of FIG. 2

FIG. 4 illustrates a detailed sectional view of an alternate arrangement for the barrier plug of FIG. 2.

FIG. 5 illustrates a flowchart of a process for installing and retrieving the barrier plug of FIG. 2.

FIGS. 6A-6F illustrate the barrier plug in various stages of deployment during the process of FIG. 5.

FIGS. 7A-7F illustrate the barrier plug in various stages of retrieval during the process of FIG. 5.

FIGS. 8A-8F schematically illustrate an alternative embodiment of deployment and retrieval of the barrier plug in which a landing section is used at the end of the expandable sand screen.

DETAILED DESCRIPTION

Embodiments of the present disclosure include a barrier plug having a plurality of dogs and a barrier element. In the well hole, a nipple or conduit component is installed below the liner hanger of the lower completion, and an expandable sand screen section is installed below the nipple. The barrier plug is positioned on a work string below an expansion tool for an expandable sand screen (ESS) system, and the work string and plug are run in the well hole. As the sting is lowered, the barrier plug and expansion tool are passed through the nipple and are run through the expandable sand screen section.

Once the screen has been expanded, the work string is pulled up so that the barrier plug passes out of the screen and enters the nipple. In one arrangement, locator dogs on the plug are activated to engage corresponding grooves on the inside of the nipple to set the plug, and locking dogs are activated to engage corresponding grooves on the inside of the nipple to lock the plug in the nipple. In another arrangement, one set of dogs is used for both locating and locking the plug inside the nipple. The work string is then pulled further up, and the force deforms the barrier element on the plug against the inside of the nipple to create a sealed barrier in both directions through the nipple. Later during production, the barrier plug can be disengaged from the nipple and carried on a running tool attached to the bottom of the upper completion. When the upper completion is later pulled, the barrier plug and barrier element can again be set in the nipple to create a sealed barrier. Because the barrier plug can be set and removed as desired, it provides flexibility for well operations.

The nipple in which the barrier plug is set and locked can have a substantially large inside diameter so that well operations can use various forms of equipment (e.g., an expansion tool) beyond the nipple. In one alternative, a flow control bottom assembly can be installed below the nipple so that fluid pumped off the bottom can be used to open the barrier plug rather than unlocking the plug and holding on to it with the upper completion. If the barrier plug is installed on the upper completion and needs to be removed for whatever reason, the barrier plug can be cut or knocked off the end into the rathole. The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure.

FIGS. 1A-1L schematically illustrate a barrier plug 50 according to the present disclosure as used with a lower completion having an expandable sand screen (ESS) system. In FIGS. 1A-1F, the barrier plug 50 is shown in deployment stages #1 through #6. In these stages, the barrier plug 50 is used with an expansion tool 22 to expand an ESS section 26 and is then set to form a sealed barrier between the upper and lower completions.

As shown in the first stage #1 of FIG. 1A, a liner hanger 12 has been set in a casing 12 of the well hole. A nipple 30, a coupling 24, and ESS section 26 attach to the liner hanger 12 in the lower completion, and the ESS section 26 extends beyond the casing 10 into the open hole of the well. The ESS expansion tool 22 and the barrier plug 50 are attached to the end of a work string 20 and are lowered into the lower completion to start the expansion of the ESS section 26. While the work string 20 is lowered, a pre-expansion cone 52 on the barrier plug 50 and the ESS expansion tool 22 expand the ESS section 26.

At the second stage #2 of FIG. 1B, expansion of the ESS section 26 has been completed, and the work string 20 has started to be pulled out of the hole. As shown, the inside surface of the nipple 30 defines upper grooves 34 and lower grooves 36 that will be used to set the barrier plug 50 within the nipple 30 during subsequent stages.

At the third stage #3 in FIG. 1C, the barrier plug 50 has been positioned relative to the nipple 30, and fluid pressure has been applied down the work string 20 to the plug 50 to activate locator dogs 54 on the outside of the barrier plug 50. As the barrier plug 50 is raised by the work string 20, the activated locator dogs 54 engage the upper grooves 34 on the inside of the nipple 30 to set the barrier plug 50 properly in the nipple 30.

In the fourth stage #4 of FIG. 1D, while the locator dogs 54 and grooves 34 set the barrier plug 50 in the nipple 30, the work string 20 is further pulled up to activate locking dogs 56 on the outside of the barrier plug 50. When activated, the locking dogs 56 engage the lower grooves 36 in the nipple 30 and lock the barrier plug 50 in place.

In the fifth stage #5 of FIG. 1E, while the barrier plug 50 remains locked in the nipple 30 by dogs 56, the work string 20 is further pulled up, and the barrier element 58 is deformed and set against the nipple 30. Once set, the barrier element 58 forms a sealed barrier that isolates the lower completion having the ESS section 26 from the upper completion. Finally, at the sixth stage #6 of FIG. 1F, the end of the work string 20 is detached (unlatched) from the barrier plug 50 and is pulled to the surface.

With the barrier plug 50 locked in position and the barrier element 58 set, various well operations can be performed while the lower completion remains isolated from the upper completion. This isolation can minimize fluid loss to the lower completion during these well operations. Once ready, the barrier plug 50 can be removed from the nipple 30 to allow production to proceed in the lower completion. Accordingly, FIGS. 1G-1L show retrieval stages #7 through #12 in which the barrier plug 50 is attached to a production stinger 40, is lowered into the ESS section 26, and is then reset to form the sealed barrier between the upper and lower completions.

In stage #7 of FIG. 1G, the stinger 40 of the upper completion is run in the casing 10, and a snap latch 42 on the stinger 40 is lowered into the end of the barrier plug 50 to connect to the barrier plug 50. At stages #8 and #9 in FIGS. 1H-1I, further lowering of the stinger 40 frees the barrier plug 50 by releasing the barrier element 58, the locking dogs 56, and locator dogs 54 from the nipple 30. (Stages #7 through #9 are essentially the reverse of the deployment stages #3 through #6 shown in FIGS. 1C-1F).

At stage #10 of FIG. 1J, further lowering of the stinger 40 pushes the barrier plug 50 into the ESS section 26 of the lower completion, and production can be started through the ESS section 26 and the perforations in the stinger 40. At stage #11 of FIG. 1K, the upper completion is pulled up to set and lock the barrier plug 50 back into the nipple 30 using the previously described deployment stages #3 through #6 in FIGS. 1C-1F. In this way, the barrier plug 50 and barrier element 58 can once again be set at stage #12 of FIG. 1L to isolate the upper completion from the lower completion. The barrier plug 50 can also be retrieved and removed from the well if desired.

Although the embodiment of the barrier plug 50 discussed herein has been described as having two sets of dogs (i.e., locator dogs 54 and locking dogs 56), an alternative embodiment of the barrier plug 50 may only include one set of dogs positioned around the plug 50. This one set of dogs may be used to both locate and lock the plug 50 in the nipple 30 when activated. In addition, the one set of dogs may be activated by spring bias, by moveable mandrels, by hydraulic pressure pumped to the plug 50 via the work string 20, or by any combination of these activation techniques.

Given the above description of how the barrier plug 50 can be used with an ESS system, we now turn to additional details of the barrier plug 50 as shown in FIG. 2 and as detailed in FIGS. 3A-3C. As best shown in FIG. 2 and as discussed previously, the barrier plug 50 includes the pre-expansion cone 52, the plurality of locator dogs 54, the plurality of locking dogs 56, and the barrier element 58. In addition to these previously described elements, the barrier plug 50 includes a housing element 60 comprised of a top housing 120, a middle housing 130, and a lower housing 160 connected together and defining an open conduit 62 therethrough. In addition, the barrier plug 50 includes a mandrel element 70 that defines an internal passage 72 and is positioned in the open conduit 62 of the housing element 60. The mandrel element 70 is comprised of an upper mandrel 140, an intermediate mandrel 190, and a lower mandrel 200.

As best shown in the detailed view of FIG. 3A, a snap latch mechanism 110 is used to removably connect the barrier plug 50 to well components, such as an expansion tool (22; FIG. 1A) or a stinger (40; FIG. 1G). A distal end of the snap latch mechanism 110 can removably position in the upper housing 120, in which the upper mandrel 140 and a sleeve 150 are positioned. A latch 112 and seals 114 on the snap latch mechanism 110 engage corresponding components of the sleeve 150 using a conventional snap latch arrangement.

The upper mandrel 140 is moveable in the upper housing 120 and holds upper and lower stop dogs 142 and 144 that can be selectively caught in catches 122 and 124 as discussed below. The sleeve 150, which snap latches to the snap latch mechanism 110, is moveable within the upper mandrel 140, and its movement is restricted by engagement with the stop dogs 142 and 144 held by the upper mandrel 140. In particular, upper and lower narrow portions 152 and 156 visible in FIGS. 3A-3B separated by a wider portion 154 visible in FIG. 3A on the sleeve 150 enable the stop dogs 142 and 144 to be pushed or retracted from upper and lower stop catches 122 and 124 depending on the position of the upper mandrel 140 and sleeve 150. (As shown in FIG. 3A, the upper stop catch 122 is formed in the inside diameter of the upper housing 120, while the lower stop catch 124 is formed at the juncture of the upper housing 120 and the middle housing 130.)

As best shown in the detailed view of FIG. 3B, the bottom of the upper mandrel 140 connects to the intermediate mandrel 190 that in turn connects to the top of the lower mandrel 200. As best shown in FIG. 3C, the bottom of the lower mandrel 200 connects to the pre-expansion cone 52 at the lower end of the barrier plug 50. (As best shown in FIG. 2, the pre-expansion cone 52 closes off the inner passage 72 through the mandrel element 70.)

Several components are positioned on the intermediate and lower mandrels 190 and 200 and include a piston 170, the locator dogs 54, the locking dogs 56, and the barrier element 58. As shown in FIG. 3B, the piston 170 is positioned on the intermediate mandrel 190 and has a seal engaging the mandrel 190. The piston 170 is moveable in the annulus formed between the intermediate mandrel 190 and the housings 130, 160 when fluid pressure communicated from the conduit of the intermediate mandrel through passages 194 forces the piston 190 upwards towards the upper mandrel 140. A shoulder 192 on the intermediate mandrel 190 below the passages 194 has a seal engaging the piston 170 and stops downward movement of the piston 190.

The plurality of locator dogs 54 are positioned around the intermediate mandrel 190 and are moveable in and out of slots 162 defined in the lower housing 160. Springs 184 push the locator dogs 54 out of the slots 162, but the spring force is not applied until extended ends 182 of the locator dogs 54 are released by extended ends 172 of the moveable piston 170. (The position in FIG. 3B shows the extended ends 172 of the moveable piston 170 engaging the extended ends 182 of the locator dogs 54, thereby holding the dogs 54 in the slots 162 against the force of the springs 184.) The locator dogs 54 define upward orientated shoulders 181 to engage complimentary shoulders of a groove in the nipple (30) when the plug 50 is positioned in the nipple (30) and fluid pressure has been applied to activate the dogs 54 (See e.g., FIG. 1C).

As shown at the bottom of FIG. 3B and at the top of FIG. 3C, the plurality of locking dogs 56 are positioned around the lower mandrel 200. When the lower mandrel 200 is moved up or down, a narrow portion 202, a rise 204, and a wider portion 205 on the mandrel 200 move the locking dogs 56 in and out of slots 164 defined in the lower housing 164.

As best shown in the detailed view of FIG. 3C, the barrier element 58 is also positioned around the lower mandrel 200 and is positioned between the lower housing 160 and the pre-expansion cone 52. The barrier element 58 may employ any of the sealing techniques and devices known in the art. In one embodiment and as shown, the barrier element 58 is composed of rubber or other suitable elastomeric substance and preferably has upper and lower portions 222 with a greater Durometer hardness than a central portion 224. Alternatively, for example, the barrier element 58 may be comprised of plastic chevrons, a rubber cup, or a unitary rubber element with a single Durometer hardness. As alluded to previously, the barrier element 58 can be deformed between the cone 52 and the end of the lower housing 160 to engage the inside surface of the nipple (30) to form a sealed barrier. (See e.g., FIG. 1E).

In the arrangement of FIG. 2, the barrier plug 50 has two sets of dogs 54 and 56 where the locator dogs 54 are used for first locating and later locking into the nipple's upper grooves (34) while the locking dogs 56 are used primarily for locking in the lower grooves (36). In contrast to such a two set arrangement of dogs, FIG. 4 shows an alternative arrangement for the barrier plug 50 having only one set of dogs 55 used for both locating and locking into internal grooves of a nipple (30). In this arrangement, fluid pressure in the central bore of the intermediate mandrel 190 actuates the piston 170, releasing extended ends 182 of the dogs 55 and allowing springs 184 to push the dogs 55 out of the slots 162 in the housing 160. While the barrier plug 50 is moved upward within the nipple (30), the biased and extended dogs 54 can thereby engage a corresponding groove in the nipple (30) to set the plug 50 in its proper location in the nipple (30). Further upward pulling on the mandrel 190 then brings the lower mandrel 200 with its angled shoulder 205 behind the extended dogs 55 to lock the dogs 55 in place in the grooves on the nipple (30). Therefore, as can be seen in this alternate arrangement, only one set of dogs 55 can be used on the barrier plug 50 for both locating and locking the plug 50 in the nipple (30).

Given the above details of the barrier plug 50, we now turn to a process 300 of deploying and retrieving the barrier plug 50 as shown in the flowchart of FIG. 5. The arrangement of the components of the barrier plug 50 during the various stages of the process 300 are illustrated in FIGS. 6A-6F and 7A-7F. In particular, FIG. 6A shows an expansion stage 310 where the plug 50 is run on a work string, and FIGS. 6B-6F show deployment stages 321 through 325 where the plug 50 is installed in the nipple 30 to form a barrier. FIG. 7A shows a barrier stage 330 where the installed barrier plug 50 prevents fluid communication through the nipple 30, and FIGS. 7B-7F show various retrieval stages 341 through 345 where the barrier plug 50 can be connected to upper completion components.

As discussed previously, the plug 50 is initially positioned on a work string along with an expansion tool (e.g., 22 of FIG. 1A), and the pre-expansion cone 52 is used in the procedures to expand an expandable sand screen section (e.g., 26 of FIG. 1A). During these procedures, the components of the barrier plug 50 are arranged as shown in the expansion stage 310 of FIG. 6A. The snap latch mechanism 100 is connected to the snap latch 112, the dogs 54 and 56 are retracted into the housing 160, and the barrier element 58 remains undeformed between the housing 160 and the cone 52.

Once expansion is complete, the barrier plug 50 is run to a desired position relative to the nipple 30 as shown in the first deployment stage 321 in FIG. 6B. Here, the piston 170, which holds the locator dogs 54, is activated by pumping fluid pressure through the mandrels 140, 190, and 200. As mentioned previously, the fluid pressure in the central bore of the intermediate mandrel 190 passes through passages 194 and forces the piston 170 upwards. The upward moving piston 170 releases the extended ends 182 of the locator dogs 54 and allows the springs 184 to push the locator dogs 54 out of the slots 162 in the housing 160. While the barrier plug 50 is moved upward within the nipple 30, the extended locator dogs 54 can engage corresponding grooves 34 in the nipple 30 to set the plug 50. The upward facing shoulders 181 on the locator dogs 54 allow the dogs 54 to engage the grooves 34 when the plug 50 is moved upward but not downward. Also, due to differences in shape, the locator dogs 54 cannot engage the lower grooves 36 defined in the nipple 30 intended for the locking dogs 56. At the end of this first stage 321, the components of the barrier plug 50 are arranged as shown in FIG. 6B.

In the second deployment stage 322 in FIG. 6C, upper components (not shown) pull up on the snap latch mechanism 110, which moves the sleeve 150 upward as well. Consequently, the lower stop dogs 144 that originally engaged the lower catch 124 in the previous stage 302 are allowed to retract into the lower narrow portion 156 of the sleeve 150. Once the lower stop dogs 144 are retracted, the mandrel 140, sleeve 150, and the snap latch mechanism 110 are pulled within the housing 120, which is stopped by the engagement of the locator dogs 54 with the nipple 30. At the end of this second stage 322, the components of the barrier plug 50 are arranged as shown in FIG. 6C.

In the third deployment stage 323 in FIG. 6D, upper components (not shown) continue to pull up on the snap latch mechanism 110, which also now moves the mandrel 140 connected to the intermediate mandrel 190 and the lower mandrel 200. With the upward movement of the lower mandrel 200, the rise 204 and wider portion 206 of the mandrel 200 push the locking dogs 56 out of the slots 164, causing the dogs 56 to engage the locking grooves 36 in the nipple 30. This engagement will hold the barrier plug 50 in position within the nipple 30 during subsequent stages. At the end of this third stage 323, the components of the barrier plug 50 are arranged as shown in FIG. 6D.

In the fourth deployment stage 324 in FIG. 6E, the upper components (not shown) continue to pull up on the snap latch mechanism 110. The pulling causes the mandrels 140, 190, and 200 to move upward relative to the housings 120, 130, and 160, which are held to the nipple 30 by the dogs 54 and 56. The lower mandrel 200 further compresses the springs 184 for the locator dog 54, and the wider portion 206 keeps the locking dogs 56 set. With the upward movement of the lower mandrel 200, the pre-expansion cone 52 deforms the barrier element 58 against the end of the lower housing 160. The deformed barrier element 58 now tightly engages the inner walls of the nipple 30, and the resulting seal or barrier prevents fluid from passing through the nipple 30 and components of the plug 50. At the end of this fourth stage 324, the components of the barrier plug 50 are arranged as shown in FIG. 6E.

In the fifth deployment stage 325 in FIG. 6F, the upper components (not shown) continue to pull up on the snap latch mechanism 110. Because the mandrels 140, 190, and 200 are now prevented from further upward movement by the compressed barrier element 58, the snap latch mechanism 110 moves the sleeve 150. As a result, the upper stop dogs 142 are now pushed into the upper catch 122 in the upper housing 120 by the wider portion 154 of the sleeve 150. Also, the upper end of the upper mandrel 140 engages the upper end of the upper housing 120. The compression ring 118 around the upper part of the sleeve 150 has been moved into an expanded portion of the upper mandrel 140. As a consequence of these various actions, the snap latch 112 is disengaged, allowing the snap latch mechanism 110 to disconnect from the sleeve 150. At the end of this fifth stage 325, the components of the barrier plug 50 are arranged as shown in FIG. 6F.

From this point, the upper components (not shown) and snap latch mechanism 110 can be removed. Then, as shown in the barrier stage 330 of FIG. 7A, various operations can be performed while the barrier created by the remaining components of the barrier plug 50 prevent fluid from passing between upper and lower portions of the well components through the nipple 30. When the barrier is no longer needed, the remaining components of the barrier plug 50 can be attached to the upper completion components by performing a number of retrieval stages 341 through 345, which are essentially the reverse of the previous deployment stages 321 through 325 so that they are not described in detail.

FIGS. 8A-8F illustrate an alternative embodiment of deployment and retrieval of the barrier plug 50 in which a landing section 28 is used. In the present embodiment, the landing 28 is installed on the distal end of ESS section 26 of the lower completion and is adapted to hold or house the barrier plug 50 apart from any work string or the like. In a preferred embodiment, the barrier plug 50 is shear pinned in the landing 28 by shear screws (not shown) or the like. Alternatively, the landing 28 can have grooves on its inner surface just like the nipple 30 so that the barrier plug 50 can be set and locked into the landing 28 using the same procedures used with respect to the nipple 30.

During an expansion stage #1 in FIG. 8A, the ESS expansion tool 22 on the end of the work string 20 are lowered into the lower completion to start the expansion of the ESS section 26, while the barrier plug 50 remains in the landing 28. When expansion is complete and it is desired to create the sealed barrier with plug 50 between the upper and lower completions, the snap latch 42 on the work string 20 at stage #2 in FIG. 8B is connected (latched) to the barrier plug 50 in the landing 28, and the barrier plug 50 is removed from the landing 28. (How the plug 50 is removed from the landing 28 depends on how it is initially installed therein. For example and as preferred, if the plug 50 is shear pinned in the landing 28, the plug 50 may simply be pulled from the landing 28 to shear it away from the pins holding it. If it is locked in the landing 28, the reverse of the deployment stages #3 through #6 in FIGS. 1C-1F may be used to remove it).

At the third stage #3 in FIG. 8C, the barrier plug 50 is set and locked in the nipple 30 to create the sealed barrier using the procedures described previously. In the fourth stage #4 in FIG. 8D, the barrier plug 50 remains locked in the nipple 30 and the work string 20 has been detached (unlatched) so that various well operations can be performed while the lower completion remains isolated from the upper completion.

Once ready, the barrier plug 50 can be removed from the nipple 30 to allow production to proceed in the lower completion. Accordingly, in stage #5 in FIG. 8E, the production stinger 40 is lowered to the barrier plug 50, and the barrier plug 50 is unlocked from the nipple 30 using previously described procedures. Then, as shown, the stinger 40 and plug 50 are lowered into the ESS section 26. Finally, at stage #6 in FIG. 8F, the barrier plug 50 is again positioned in the landing 28. In this way, the barrier plug 50 can be positioned out of the way so that production can be started through the ESS section 26.

With the benefit of the present disclosure, it will be appreciated that various modifications can be made to the components. For example, the barrier plug 50 has been described as being used in conjunction with an Expandable Sand Screen system. However, the barrier plug 50 can be used for various other purposes to form a barrier in a well. For example, the barrier plug 50 can generally be used in applications where the completion is open to the formation. In addition, the barrier plug 50 has been described as being used in conjunction with a nipple 30 having inner grooves, where the nipple 30 is positioned below a liner hanger in a well. However, the nipple can install above a liner hanger, can install on a separate run below a packer in the well, or can install in other locations.

Furthermore, it will be appreciated that the barrier plug 50 can be used with any type of conduit element having grooves and that the conduit element can be positioned in various locations of a well. For example, the conduit element can be installed in a position somewhere in the casing and not necessarily below a liner hanger, and the conduit element can be installed on a separate run in the well below a packer. Moreover, the conduit component can be either a separate component such as the nipple 30 that attaches to the liner hanger 12 and the expandable sand screen 26 or can be integral with either one or both of these components.

The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof. 

1. A barrier forming apparatus deployable through a conduit in a well, the apparatus comprising: a housing having a first end, a second end, and a side, the side defining at least one first slot; a coupler positioned at the first end of the housing and removably coupling to a work string; a mandrel positioned in the housing and moveable with the coupler, the mandrel having a distal end extending beyond the second end of the housing; at least one first dog positioned between the mandrel and the housing and being moveable between a retracted position and an extended position within the at least one first slot by movement of the mandrel; and a barrier element positioned between the second end of the housing and the distal end of the mandrel and being deformable by movement of the distal end of the mandrel towards the second end of the housing.
 2. The apparatus of claim 1, wherein the distal end of the mandrel comprises a body for at least partially expanding an expandable sand screen in the well.
 3. The apparatus of claim 1, wherein the coupler comprises a snap latch latchable to a complimentary element on the work string.
 4. The apparatus of claim 1, wherein the barrier element comprises an elastomeric sleeve positioned about a portion of the mandrel.
 5. The apparatus of claim 4, wherein the elastomeric sleeve comprises edge portions with a greater Durometer hardness than a central portion.
 6. The apparatus of claim 1, wherein the mandrel comprises a narrow portion and a wide portion, the mandrel element being moveable to a first position in which the narrow portion is adjacent the at least one first dog and the at least one first dog is moveable to the retracted position in the at least one first slot, the mandrel being movable to a second position in which the wide portion is adjacent the at least one first dog and the at least one first dog is movable to the extended position in the at lease one first slot.
 7. The apparatus of claim 6, wherein the at least one first dog in the extended position is engageable with at least one first groove defined in an inner passage of the conduit.
 8. The apparatus of claim 1, further comprising at least one second dog positioned between the mandrel and the housing, the housing defining at least one second slot, the at least one second dog being movable between a retracted position and an extended position within the at least one second slot.
 9. The apparatus of claim 8, wherein the at least one second dog in the extended position lockably engages at least one groove defined in an inner passage of the conduit in a first direction toward the first end of the housing.
 10. The apparatus of claim 8, further comprising: a piston movable from a first position to a second position on the mandrel by pressure communicated from the work string coupled to the coupler, the piston in the first position engaging the at least one second dog in the retracted position, the piston in the second position disengaging the at least one second dog; and a biasing element biasing the at least one second dog from the retracted position toward the extended position within the at least one second slot.
 11. The apparatus of claim 10, wherein the mandrel defines a central bore communicating with the work string and defines a passage communicating from the central bore to an outside surface of the mandrel, the mandrel having a first seal on one side of the passage and engaging the piston, the piston having a second seal engaging the mandrel on another side of the passage.
 12. A barrier forming system for a well, the system comprising: a conduit deployable in the well, the conduit having an inner passage and defining at least one first groove in the inner passage; and a plug deployable through the conduit, the plug at least including: a housing having a first end, a second end, and a side, the side defining at least one first slot, a coupler positioned at the first end of the housing and removably coupling to a work string, a mandrel positioned in the housing and moveable with the coupler, the mandrel having a distal end extending beyond the second end of the housing, at least one first dog positioned between the mandrel and the housing and being moveable between a retracted position and an extended position within the at least one first slot by movement of the mandrel, the at least one first dog in the extended position being engagable with the at least one first groove in the inner passage of the conduit, and a barrier element positioned between the second end of the housing and the distal end of the mandrel, the barrier element being deformable by movement of the distal end of the mandrel towards the second end of the housing to engage the inner passage of the conduit.
 13. The system of claim 12, wherein the mandrel element comprises a narrow portion and a wide portion, the mandrel element being moveable to a first position in which the narrow portion is adjacent the at least one first dog and the at least one first dog is movable to the retracted position in the at least one first slot, the mandrel being moveable to a second position in which the wide portion is adjacent the at least one first dog and the at least one first dog is movable to the extended position in the at lease one first slot.
 14. The system of claim 13, further comprising: a first lock positioned on the mandrel and engageable with the housing when the mandrel is in the first position; and a second lock positioned on the mandrel and engageable with the housing when the mandrel is in the second position.
 15. The system of claim 12, further comprising at least one second dog positioned in at least one second slot defined in the housing and movable between a retracted position and an extended position in the at least one second slot.
 16. The system of claim 15, wherein the conduit defines at least one second groove in the inner passage, and wherein the at least one second dog in the extended position lockably engages the at least one second groove in a first direction toward the first end of the housing.
 17. The system of claim 15, further comprising: a piston movable from a first position to a second position on the mandrel by pressure communicated from the work string coupled to the coupler, the piston in the first position engaging the at least one second dog in the retracted position, the piston in the second position disengaging the at least one second dog; and a biasing element biasing the at least one second dog from the retracted position toward the extended position within the at least one second slot.
 18. The system of claim 17, wherein the mandrel defines a central bore communicating with the work string and defines a passage communicating from the central bore to an outside surface of the mandrel, the mandrel having a first seal on one side of the passage and engaging the piston, the piston having a second seal engaging the mandrel on another side of the passage.
 19. A well barrier method comprising the steps of: installing a conduit in the well, the conduit defining one or more inner grooves; deploying a plug in the well on an end of a work string; engaging one or more dogs on the outside of the plug in the one or more inner grooves to hold the plug in the conduit; deforming a barrier element against the conduit by pulling up on the work string; and disconnecting the end of the work string from the plug.
 20. The method of claim 19, wherein installing the conduit comprises: installing the conduit below a liner hanger in the well, and installing an expandable sand screen below the conduit.
 21. The method of claim 20, wherein deploying the plug in the well on the end of the work string further comprises using a cone shaped portion on a distal end of the plug to at least partially expand the expandable sand screen.
 22. The method of claim 19, wherein engaging the one or more dogs on the outside of the plug in the one or more inner grooves to hold the plug in the conduit comprises: activating at least one of the one or more dogs on the outside of the plug to engage at least one of the one or more grooves by applying fluid pressure through the work string.
 23. The method of claim 22, wherein activating the at least one dog comprises: biasing the at least one dog after applying fluid pressure; and lockably engaging the at least one biased dog against the at least one groove in only a first direction.
 24. The method of claim 19, wherein deforming the barrier element against the conduit by pulling up on the work string comprises deforming the barrier element between an end of a mandrel of the plug and a portion of a housing of the plug, the mandrel being movable relative to the housing by the pulling up of the work string.
 25. The method of claim 19, wherein deforming the barrier element against the conduit by pulling up on the work string comprises: locking a movable mandrel within the plug; and locking the one or more dogs in the one or more inner grooves with the locked movable mandrel. 